ID - What could this be?

[OK-Coral]

Hi guys, I have 2 month old Fluval Evo with live rock, live sand, CUC and a couple of clowns (literally and metaphorically). 

I was taking a look at the tank this morning and spotted something I hadn't seen before. It appears to be in a tiny white spiral like shell or body with a red 'head' protruding with lots of small appendages. When any of the crabs come near it he will retract then emerge again a minute later. 

 

The head almost looks a little feather duster like to me but he appears to be rooted to the live rock.

 

I've added a couple of pictures, one retracted and another when he's out. I apologize for the poor quality of the 'out' picture but it's pretty far back in the tank and this thing is tiny (Biro tip sized)

 

Any help will be greatly appreciated.

[patback]

Simple red fan worm. Worn get much bigger than that. 

[OK-Coral]

Ahhh, many thanks. So should be nothing to worry about hopefully!

[patback]

30 minutes ago, OK-Coral said:

Ahhh, many thanks. So should be nothing to worry about hopefully!

Not at all.  If anything, it is an area of focus until  you get enough coral to fill the rock work up.  My personal favorite thing in reef tanks are the tiny creatures such as these. 

[mndfreeze]

I love the micro-life in a reef tank.  I'm sad I started with pretty much dead rock (except a biofilm) this time around because it really lacks all the neat stuff like this.  I'm slowly finding ways to purposely introduce them.  

 

All the different mini featherduster / fan worms not only look pretty or cool, but are micro water filters as well and help break down nutrients in your tank, adding to the over all filtration, though how much benefit is of course impossible to measure for us.  

[MainelyReefer]

Spirorbid worms